SOLUTION: If sin x = 0.3, find sec x?

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Question 825854: If sin x = 0.3, find sec x?
Found 2 solutions by lwsshak3, math-vortex:
Answer by lwsshak3(11628) About Me  (Show Source):
You can put this solution on YOUR website!
If sin x = 0.3, find sec x?
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cosx=√(1-sin^2x)≈√(1-0.3^2)≈√(1-0.9)≈√0.1≈0.316
secx=1/cosx≈3.162

Answer by math-vortex(648) About Me  (Show Source):
You can put this solution on YOUR website!
Hi, there--

THE PROBLEM:
If sin x = 0.3, find sec x?


A SOLUTION:

We know that sin x = 0.3.

Use the trig identity to find the value of cos x. 

%28sin%28x%29%29%5E2%2B%28cos%28x%29%29%5E2=1

Substitute 0.3 for sin x.
%280.3%29%5E2%2B+%28cos%28x%29%29%5E2=1
0.09%2B%28cos%28x%29%29%5E2=1
%28cos%28x%29%29%5E2=1-0.09=0.91
cos%28x%29=sqrt%280.91%29

By definition, sec x = 1/cos x
sec%28x%29=1%2F%28sqrt%280.91%29%29
sec%28x%29+=+sqrt%280.91%29%2F0.91

This irrational number is an exact answer for sec x. If you convert this to a decimal, it will be an approximation.

Hope this helps! Feel free to email if you have any questions.

Mrs. Figgy
math.in.the.vortex@gmail.com